We homeschool our children, but safety was never really one of the concerns that brought us to that decision. If we decided we had to send them to school now, it still wouldn't be one of the considerations. School shootings are such a small probability risk that I just don't worry about it.
Our decision involved a whole range of other things, the first being that we actually CAN (we can make it on my income alone, and I recognize the privilege that represents). You can get a great education at public school (I did). It's like anything else; you get out of it what you're willing to put into it. My children happen to be getting a FANTASTIC education from my wife at home, and that is one of the major factors. It also makes our schedule for the family very flexible, and it gives us a choice in almost everything.
Another factor is that they are not being indoctrinated into looking to the government to provide things for them like education and opportunity. They are being taught ACTIVELY that they can provide these things for themselves. The government is also not teaching them it's own version of right and wrong, which is hopelessly out of whack. They are getting OUR values, and if someone outside our family has a problem with that, that's tough.
As far as socialization, this is not an issue for most of the homeschoolers that I know. It is largely a straw man brought up by those that oppose homeschooling, and people that stereotype them as "anti-social weirdos" are mostly clueless. Yes this happens, but not often. The cases where that is true just get a lot of press because of the agenda of those reporting on it.
My children are involved in FAR more extracurricular activities than their public school friends including sports, music, drama, community service, etc. Relying on a public school environment to socialize your kids is sometimes like throwing them to the wolves and walking away, or throwing them into the deep end of the pool. Sometimes it works out great and makes them stronger, and sometimes it screws them up beyond all recognition. It depends on the input FROM PARENTS. My children are introduced to the complications of social interaction with lots of feedback, discussion, role playing, and analysis. It would be the same in public school, but with the activities they have as homeschoolers, they get the CHOICE of dealing with complicated and thorny social interactions in doses THEY can adjust as they need to. That works for us.
Niether of my kids has ever been to school. They are both in high school now (daughter 11th and son 9th grade). They are smart, social, well adjusted and both of them shoot great!
Deal with it.